Even as LTE and LTE Advanced (4th Generation cellular systems) are being deployed, work is already starting on their successor: 5G. This paper describes the needs that demand continued development of mobile and fixed-line communications systems, and explains some background on who is involved and what is currently happening in bringing 5G from theory to reality.
If we’re all to use our mobile devices to work and play anywhere, we want access to streaming services and all our own “stuff”, instantly, on devices as small as a smartphone or as large as the screen in an auditorium – properly formatted for the size of the screen, of course. We’re already socially networked, 24 hours per day, 7 days a week. We want to be able to share versions of our stuff – photos, video, data, whatever – with friends, colleagues, and customers – wherever they may be.
In the same way, we don’t want to buy software applications we don’t need. Instead, we want to rent the applications we need to process our data for just as long as we need them. This is the vision of true “cloud computing”, as opposed to just cloud storage, and its reality depends almost entirely on high-speed connectivity.
This need for high-speed connectivity is the common denominator as we look ahead to fifth-generation or 5G mobile networks. Achieving 24/7 access to, and sharing of, all our “stuff” requires that we continue on our current path: going far beyond simple voice and data services, and moving to a future state of “everything everywhere and always connected”.
For most of the 20th century, network operators used the work of Danish mathematician and engineer A.K. Erlang (1878-1929) as the basis for network planning: the central idea was predicting the number of simultaneous users a telecommunications network would have to support. As long as networks were used mainly for voice calls, the same broad principles applied to mobile networks, with the added flexibility of using a smaller cell size in geographic “hot spots” where more users could be expected and cell capacity could be exceeded.
Today, as the provisioning and take-up of data services on both fixed-line and mobile networks continues to rocket, the rules of network provisioning need to be re-written. Data services are by their nature discontinuous. Moving to packet- rather than circuit-based service delivery allows more users to share the same resource even though the process of directing data becomes more complex.
Three main delivery mechanisms for general use have emerged: Data Over Cable Service Infrastructure Specifications (DOCSIS) modems using existing cable TV infrastructure, Asynchronous Digital Subscriber Line (ADSL) modems using the copper of fixed-line telephony, and third and fourth generation cellular networks with higher cell capacities (aka “mobile broadband”).
Successive advances in mobile network technology and system specifications have provided higher cell capacity and consequent improvements in single-user data rate. The increases in data rate have come courtesy of increased computing power, and increased modulation density made possible by better components, particularly in the area of digital receivers. Along with the latest mobile network specifications, there is a concurrent move to the Evolved Packet Core (EPC) – the simplified all-packet network architecture designed specifically to improve data throughput and latency, and to better match the core mobile network to the architecture of fixed-line networks. In fixed-line networks, higher speeds for data-intensive services come via the extenstion of fiber optic cable into local distribution. Copper has become the “last yards”, rather than “last mile” medium, as fiber-to-the-curb (sometimes “fiber-to-the-cabinet”) and even fiber-to-the-home networks provide the high-speed broadband connectivity that’s required for high-definition video streaming and like services.These improvements have produced a “chicken and egg” conundrum for mobile network operators: the more data capacity they make available, the more complex and data-hungry equipment the device manufacturers offer, and the more sophisticated the demands of end-users become. The latest of these demands is “seamless connectivity” – the ability to move an application amongst devices: for instance, tablet to phone to home entertainment center – without interruption of the content. To provide this capability requires access to, and control of, the content over multiple networks: WiFi hotspot, cellular and landline. (It’s not just a technical challenge –associated billing needs a plethora of roaming agreements as well.)
In all this, there is one certainty that must be considered: wireless spectrum is limited. In the long run, this must mean only those connections which MUST be mobile should be wireless. As much service delivery as possible must be routed through fixed (fiber) networks to as close as possible to the point of consumption. We’re already seeing the rise of television and radio services delivered over the internet, with more choice of material and timing than terrestrial or satellite broadcast can match. And in mobile networks, today’s WiFi offload becomes the starting point for the norm of tomorrow, freeing up cellular system capacity to give mobile users the best possible service.
In the mobile world, capacity gains come essentially from three variables: more spectrum, better modulation efficiency and better frequency re-use through progressively smaller cell size. The fourth generation networks currently being built use more frequency bands than previous generations and can use broader channel bandwidths. However, with mobile data consumption currently forecast to almost double year-on-year for the next five years, the network operators maintain they will struggle to meet long-term demand without even more spectrum. Freeing up frequency bands currently used for other systems will become a major priority.The vision for the year 2020 that’s presented in the studies for fifth generation mobile networks “5G” is one of “everything everywhere and always connected”. It assumes devices can operate on frequencies from a few hundred megahertz to (in some cases) eighty gigahertz. Indoor cell sizes may be as small as a single room. It employs pico- and femto-cells to maximize frequency reuse at RF. ITU’s definition of 4G has an expectation of 1 Gbps single-user data rate. The goal for 5G is not necessarily to increase this, but to have a high-capacity network capable of delivering this rate to a much bigger user communiy; in other words to provide higher aggregate capacity for more simultaneous users, or higher level spectral efficiency. None of the studies have specific details of the core network that joins everything together, but they assume the seamless connectivity mentioned earlier will be a given. Nor do they suggest solutions to the issue of power consum ption in mobile devices that must be able to interact with such a network. However, though it is envisioned as simultaneously using multiple air interface technologies, 5G is presented as a stand-alone wireless communications concept, not as part of an integrated telecommunications system. Though it does talk about the integration of cellular and wireless LAN, it still separates the mobile vision from fixed-line service delivery, which may ultimately be the best solution for some home and office applications.
To support vastly increased numbers of devices and performance requirements, the 5G studies postulate the key network attributes that will be required: huge numbers of small cells with capacity enhanced through high-order spatial multiplexing (MIMO), cell data rates of the order of 10 GB/s and round-trip latency of 1 ms. With these, the system will support immersive virtual reality, M2M monitoring and control of literally billions of sensors, and support the massive data collection and distribution needs of the “Internet of Things”. With the massive infrastructure costs involved, it’s difficult to see individual operators affording the investment separately; shared, jointly-managed resources have been predicted as being much more likely.
Keysight Technologies measurement and application experts are working with industry experts to anticipate the growing complexities of 5G so the industry can accelerate these new technologies.
Visit Keysight at keysight.com/find/lte and keysight.com/find/lte-advanced to see the latest solutions that can be used for 4G and 5G.
The players in 5G
Hari Balakrishnan and Dina Katabi co-directors
Also known more formally as the MIT Center for Wireless Networks and Mobile Computing, this new organization pulls together more than a dozen MIT professors and their research groups to work on next-generation wireless networks and mobile computing.
The work done at the center is designed to make an impact on technology users: Wireless@MIT boasts a "strong industrial partnership" with Microsoft, Cisco, Intel, Telefonica, Amazon, STMicroelectronics, and MediaTek -- and says it aims to influence standards and products.
Research at Wireless@MIT is currently focused on four areas: spectrum and connectivity, mobile applications, security and privacy, and low-power systems.
METIS is an EU-funded, Ericsson-led, consortium of 29 organizations with a 27 million Euro budget and more coming from the European Commission is aimed at replicating Europe’s worldwide success with GSM and subsequent technologies. It will "develop a system concept that delivers the necessary efficiency, versatility and scalability... investigate key technology components supporting the system, and...evaluate and demonstrate key functionalities." The majority of participants are universities and mobile network operators, with industry partners including Alcatel-Lucent, BMW, Huawei, Nokia, and Nokia Siemens Networks (NSN).
METIS is co-funded by the European Commission as an Integrated Project under the Seventh Framework Programme for research and development (FP7). It will run for 30 months.
Technical University of Dresden, Germany
Gerhard P. Fettweis, Vodafone Chair Professor
MWJ Article Link – A 5G Wireless Communications Vision
TU-Dresden previously pioneered 3G systems research in association with the Vodafone Chair Mobile Communications Systems, which is dedicated to cutting-edge research in wireless communication technology. Their vision for a next-generation system is user-centric, with required system attributes based on perceived future usage models: “The Internet of Things”. Their vision for 5G is to provide a new unified air interface to cover cellular, short-range and sensor technology that can deliver 10 Gbps, 1 ms latency and simple sensors with 10-year battery life.
Centre for Communication Systems Research (CCSR), University of Surrey, UK
Professor Rahim Tafazolli
The project will begin in 2013, and is expected to cost around £35 million ($56 million USD), where about £11.6 million will come from the UK government and the other £24 million will be provided by a group of tech companies, including Samsung, Huawei, Fukitsu Laboratories Europe, Telefonica Europe, and AIRCOM International. An expansion of the program is also being sought with further proposals going to the UK government.
“We are looking at the processors, protocols, algorithms, and techniques...we won't try to optimise the hardware implementation -- that is something the industry will do. We have developed the know-how” – quote from Professor Tafazolli.
It’s claimed that the new network will be spectrum-efficient and energy-efficient. It will also be faster, with cell speeds bumped up to a capacity of 10Gbps.
Polytechnic Institute of New York University (NYU-Poly)
Professor Theodore (Ted) Rappaport
Researchers at Polytechnic Institute of New York University (NYU-Poly) have assembled a consortium of government and business support to advance beyond today’s fourth generation (4G) wireless technologies toward 5G cellular networks. The National Science Foundation (NSF) has awarded the team an Accelerating Innovation Research (AIR) grant of $800,000, matched by $1.2 million from corporate backers and the Empire State Development Division of Science, Technology & Innovation (NYSTAR), which supports the project through its longstanding partnership with NYU-Poly’s Center for Advanced Technology in Telecommunications (CATT).
The 5G project will develop smarter and far less expensive wireless infrastructure by means of smaller, lighter antennas with directional beamforming to bounce signals off of buildings using the uncrowded millimeter-wave spectrum. It will also help develop smaller, smarter cells with devices that cooperate rather than compete for spectrum.
Professor Rappaport recently joined the NYU and NYU-Poly faculty and is launching the world’s first academic research center that combines wireless communications with computing and medical applications.
China’s Ministry of Industry and Information Technology has established a working group called “IMT-2020 (5G) Promotion Group” for 5G research in February 2012.
Tokyo Institute of Technology and DOCOMO
Tokyo Institute of Technology in a joint outdoor experiment conducted recently with NTT DOCOMO, INC. succeeded in a packet transmission uplink rate of approximately 10 Gbps. In the experiment, a 400 MHz bandwidth in the 11 GHz spectrum was transmitted from a mobile station moving at approximately 9 km/h. Multiple-input multiple-output (MIMO) technology was used to spatially multiplex different data streams using eight transmitting antennas and 16 receiving antennas on the same frequency.
Qualcomm’s 1000x Data Challenge Presentation
The presentation “1000x Data Challenge” from Qualcomm discusses a three-fold evolution of today’s 4G standards. It proposes study items for 3GPP specification releases 12 and beyond relating to interworking, heterogeneous networks, self-organizing networks and steadily decreasing cell sizes. See www.qualcomm.com/1000x for presentation material and discussions.
Samsung Electronics recently announced it had made a breakthrough in wireless network technology, calling it "5G". Samsung said that its researchers "successfully developed the world's first adaptive array transceiver technology operating in the millimeter-wave Ka bands for cellular communications."
The transmissions used in the test were made at the ultra-high 28GHz frequency, which offers far more bandwidth than the frequencies used for 4G networks. High frequencies can carry more data, but have the disadvantage that they generally can be blocked by buildings and lose intensity over longer distances.
Samsung said its adaptive array transceiver technology, using 64 antenna elements, can be a viable solution for overcoming the weaker propagation characteristics of millimeter-wave bands, which are much higher in frequency than conventional wireless spectrum. The company said it "plans to accelerate the research and development of 5G mobile communications technologies, including adaptive array transceiver at the millimeter-wave bands”.
“5G mobile phone concept”
Author: Janevski, T. Fac. of Electr. Eng. & Inf. Technol., Univ. Sv. Kiril i Metodij, Skopje
Published in Consumer Communications and Networking Conference, 2009. CCNC 2009. 6th IEEE
“Evolution of Networks (2G-5G)”
Jay R. Churi, T. Sudhish Surendran, Ajay Tigdi, Shreyas, Sanket Yewale
Dept. of Comp. Sc., Padmabhushan Vasantdada Patil Pratishthan’s College of Engineering, Mumbai University, India
Published in International Conference on Advances in Communication and Computing Technologies (ICACACT) 2012 Proceedings published by International Journal of Computer Applications® (IJCA) 8